SusChEM: Controls on struvite neogenesis and reactivity in engineered and geochemical systems

技术描述磷(P)可以从人类和农业废物中回收为矿物鸟粪石（MgNH4PO4·6H2O），可以作为传统肥料的替代品。本项目探讨了从不同类型的废物中产生鸟粪石的性质和反应性，并将其与地球化学生产的鸟粪石进行了比较。该研究的目的是阐明支配鸟粪石的物理和化学性质的首要条件和参数，独立于新生的来源。鸟粪石将从养猪废水、温室废水和莫诺湖水中沉淀出来。鸟粪石回收工程系统中常用的是动植物废弃物，而Mono湖是一个历史上存在鸟粪石的地球化学系统。模型溶液，以去离子水为溶剂，将用于确定具体的控制；即pH值，离子强度，溶解有机物；关于合成的矿物性质。还将评估在起始溶液中普遍存在的微量污染物（如金属）的吸附。这一点尤其重要，因为鸟粪石性质对吸附过程的影响以前尚未确定，相反，吸附杂质对矿物结构和稳定性的影响尚不清楚。该研究将采用几种先进和创新的技术，包括P XAFS， 31P NMR， 33P放射性示踪剂和TG/DSC-FT-IR，这些技术可转移到其他磷酸盐矿物的研究中。本研究的结果可用于根据废物组成和实施条件，在工程系统中操纵鸟粪石的性质。从废物中更好地设计鸟粪石的能力将促进鸟粪石肥料的使用，并鼓励磷的可持续利用。对社会的重要性人类磷循环是不可持续的。这是因为磷是一种有限的自然资源，由于它被用作肥料，人类活动加速了它的循环。随着地质P储量的减少和全球人口的不断增加，在人类循环中损失的P需要得到补偿。这可以通过从人类和农业废物中回收磷作为磷酸盐矿物鸟粪石来实现。利用回收鸟粪石作为替代肥料源，将促进磷的可持续利用，保护天然磷资源，并限制岩石中封存的额外磷释放到人类循环中。这个项目将使人们更好地了解从各种来源，包括动物和植物废物中产生的鸟粪石的物理和化学性质。结果可用于根据废水组成和回收条件预测和潜在控制回收鸟粪石的性质和污染物含量。这提供了安全性，鸟粪石作为肥料输送到土壤中，可以按需发挥作用，不会造成污染风险，从而对土壤、农业生态系统和地球化学系统构成环境责任。最终，从废物中回收的鸟粪石作为磷的来源，通过提供一种替代的、可持续的肥料来养活不断增长的全球人口，将为人类的磷循环带来可持续性。

Technical DescriptionPhosphorus (P) can be recovered from human and agricultural wastes as the mineral struvite (MgNH4PO4·6H2O), which can be used as an alternative to traditional fertilizers. This project addresses the properties and reactivity of struvite when generated from different types of wastes, and as compared to geochemically produced struvite. The goal of the research is to elucidate the overarching conditions and parameters that dictate the physical and chemical properties of struvite, independent of source of neogenesis. Struvite will be precipitated from swine effluent, greenhouse wastewater, and Mono Lake water. The animal and plant wastes are commonly used in engineered systems for struvite recovery, and Mono Lake is a geochemical system with a historical occurrence of struvite. Model solutions, with deionized water as the solvent, will be used to determine the specific controls; i.e. pH, ionic strength, dissolved organics; on the resultant mineral properties. The sorption of trace contaminants such as metals, prevalent in starting solutions, will also be assessed. This is particularly critical because the impact of struvite properties on sorption processes has not been previously determined, and conversely the effect of sorbed impurities on the mineral structure and stability are not known. The research will implement several advanced and innovative techniques, including P XAFS, 31P NMR, 33P radiotracers and TG/DSC-FT-IR, which are transferable to the study of other phosphate minerals. Results from this research can be used to manipulate the properties of struvite in engineered systems, contingent upon waste composition and implemented conditions. The ability to better engineer struvite from wastes will advance the use of struvite fertilizers and encourage the sustainable use of P.Importance for SocietyThe human phosphorus (P) cycle is unsustainable. This is because P is a limited natural resource, the cycling of which is accelerated by human activity due to its use as fertilizer. With diminishing geologic P reserves, and an ever increasing global population, P lost in the human cycle needs to be recouped. This can be achieved by the recovery of P from human and agricultural wastes as the phosphate mineral struvite. The use of recovered struvite as an alternative fertilizer source will promote the sustainable use of P, conserve natural P resources, and limit the release of additional P sequestered in rocks to the human cycle. This project will provide an improved understanding of the physical and chemical properties of struvite when generated from a variety of sources, including animal and plant wastes. Results can be used to predict, and potentially control, the properties and contaminant content of recovered struvite based on wastewater composition and recovery conditions. This provides the security that struvite delivered to soils as fertilizer can function as required and does not pose a contamination risk, and thus an environmental liability to soils, agro-ecosystems and geochemical systems. Ultimately, the reuse of struvite recovered from wastes as a source of P will introduce sustainability to the human P cycle by providing an alternative, sustainable fertilizer to feed a growing global population.